System for autonomous lane merging

ABSTRACT

An autonomous drive system for a vehicle includes at least one environment perception sensor, a perception module, a location module, an intention prediction module, and a control module. The perception module is configured to receive signals from the at least one environment perception sensor and detect and track at least two remote vehicles in one or both of a current lane and a neighboring lane. The location module is configured to determine a location of the vehicle. The intention prediction module is configured to generate predicted trajectories for the at least two remote vehicles. The control module is configured to receive signals from the at least one environment perception sensor and receive the predicted trajectories from the intention prediction module. The control module determines a location and time for a lane change based on the predicted trajectories and controls the vehicle to change lanes at the determined location and time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/608,794, filed on Dec. 21, 2017. The entire disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The present disclosure relates to autonomous drive systems and, morespecifically, a system for autonomous lane merging for vehicles.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

The Society of Automotive Engineers (SAE) classifies autonomous drive(AD) systems into a variety of different categories based onfunctionality. Some AD systems are very basic, purely independentautomated components (such as adaptive cruise control and emergencybraking systems). Other more advanced AD systems are fullyterrain-independent autonomous driving systems. A major differencebetween the basic and complex AD systems is that, with the complex ADsystems, the responsibility to monitor current driving conditions istransferred from an operator to the autonomous drive system. Suchcomplex AD systems must operate under dense traffic conditions, and,consequently, face numerous challenging driving situations. Merging intoa densely populated lane is particularly difficult for traditionalautonomous driving systems, as there is often a need to perform complex,human-like behaviors to successfully and comfortably negotiate thesescenarios. For example, a traditional autonomous driving system may waitfor a remote vehicle to let it in; whereas a human driver may makeproactive moves, such as shift slowly over to communicate theirintention to merge to the surrounding vehicles, which are, in turn,subsequently more likely to make space. The present disclosure addressesthese differences and potential issues with the autonomous drivingsystems.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

An example autonomous drive system for a vehicle according to thepresent disclosure includes at least one environment perception sensor,a perception module, a location module, an intention prediction module,and a control module. The perception module is configured to receivesignals from the at least one environment perception sensor and detectand track at least two remote vehicles in one or both of a current laneand a neighboring lane. The location module is configured to determine alocation of the vehicle. The intention prediction module is configuredto generate predicted trajectories for the at least two remote vehicles.The control module is configured to receive signals from the at leastone environment perception sensor and receive the predicted trajectoriesfrom the intention prediction module. The control module determines alocation and time for a lane change based on the predicted trajectoriesand controls the vehicle to change lanes at the determined location andtime.

The control module of the autonomous drive system may complete a waitingto shift stage, a shifting stage, a waiting to merge stage, and amerging stage when the control module controls the vehicle to changelanes at the determined location and time.

The control module of the autonomous drive system may determine whethera distance between the vehicle and the at least two remote vehicles isless than a predetermined distance threshold and whether a difference ina velocity of the vehicle and a velocity of the at least two remotevehicles is less than a predetermined velocity threshold during thewaiting to shift stage.

The control module of the autonomous drive system may shift the vehiclein a direction toward a lead vehicle of the at least two remote vehiclesduring the shifting stage.

The control module of the autonomous drive system may complete theshifting stage when the control module controls the vehicle to crossover a lane delimiter and into the neighboring lane.

The control module of the autonomous drive system may determine whethera distance between the at least two remote vehicles is greater than apredetermined distance threshold and whether a difference in a velocityof the vehicle and a velocity of the at least two remote vehicles isless than a predetermined velocity threshold during the waiting to mergestage.

The control module of the autonomous drive system may shift the vehicleinto the neighboring lane from the current lane at the determinedlocation and time during the merging stage.

The merging stage may be complete when the vehicle has completelycrossed over the lane delimiter and the neighboring lane becomes the newcurrent lane for the vehicle.

The control module of the autonomous drive system may initiate a mergefailure recovery if a time spent in a stage exceeds a predeterminedthreshold and control the vehicle back into the current lane.

The control module of the autonomous drive system may initiate a mergefailure recovery if an abort signal is received or if one of the atleast two remote vehicles follows a path different than the projectedtrajectory that increases a risk as determined by the intentionprediction module and control the vehicle back into the current lane.

An example method for controlling an autonomous vehicle according to thepresent disclosure includes determining, by a location module, alocation of the vehicle; detecting and tracking, by a perception module,at least two remote vehicles in one or both of a current lane and aneighboring lane; generating, by an intention prediction module,predicted trajectories for the at least two remote vehicles;determining, by a control module, a location and time for a lane changebased on the predicted trajectories for the at least two remotevehicles; and controlling, by the control module, the vehicle to changelanes at the determined location and time.

The method may further include completing, by the control module, awaiting to shift stage, a shifting stage, a waiting to merge stage, anda merging stage while controlling, by the control module, the vehicle tochange lanes at the determined location and time.

The method may further include determining, by the control module,whether a distance between the vehicle and the at least two remotevehicles is less than a predetermined distance threshold and whether adifference in a velocity of the vehicle and a velocity of the at leasttwo remote vehicles is less than a predetermined velocity thresholdduring the waiting to shift stage.

The method may further include shifting, by the control module, thevehicle in a direction toward a lead vehicle of the at least two remotevehicles during the shifting stage.

The method may further include completing, by the control module, theshifting stage when the vehicle crosses over a lane delimiter and intothe neighboring lane.

The method may further include determining, by the control module,whether a distance between the at least two remote vehicles is greaterthan a predetermined distance threshold and whether a difference in avelocity of the vehicle and a velocity of the at least two remotevehicles is less than a predetermined velocity threshold during thewaiting to merge stage.

The method may further include controlling, by the control module, thevehicle to change lanes between the current lane and the neighboringlane at the determined location and time during the merging stage.

The method may further include completing, by the control module, themerging stage when the vehicle has completely crossed over a lanedelimiter and the neighboring lane becomes a new current lane for thevehicle.

The method may further include initiating, by the control module, amerge failure recovery if a time spent in a stage exceeds apredetermined time threshold, and controlling, by the control module,the vehicle back into the current lane.

The method may further include initiating, by the control module, amerge failure recovery if an abort signal is received or if one of theat least two remote vehicles follows a path different than the projectedtrajectory that increases a risk as determined by the intentionprediction module, and controlling, by the control module, the vehicleback into the current lane.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 illustrates an exemplary vehicle including an autonomous drivesystem in accordance with the present disclosure.

FIG. 2 illustrates a block diagram of the autonomous drive system inaccordance with the present disclosure.

FIG. 3 illustrates an example dense traffic condition including thevehicle of FIG. 1.

FIG. 4 illustrates a method for lane merging under dense trafficconditions in accordance with the present disclosure.

FIGS. 5A-5D illustrate a merging maneuver of the exemplary vehicle ofFIG. 1.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein are interpreted accordingly.

As previously stated, merging into a densely populated lane isparticularly difficult for traditional autonomous driving systems, asthere is often a need to perform complex, human-like behaviors tosuccessfully and comfortably negotiate these scenarios. For example, atraditional autonomous driving system may wait for a remote vehicle tolet it in; whereas a human driver may make proactive moves, such asshift slowly to communicate their intention to merge to the surroundingvehicles (by, for example, slowly shifting over), which are, in turn,subsequently more likely to make space.

The present disclosure presents a novel framework that allows autonomousvehicles to produce robust behaviors that allow for merging safely,comfortably, and efficiently into dense traffic. It combines high-levelplanning under uncertainty to effectively reason about whether aneighboring or surrounding vehicle intends to let the autonomous vehiclemerge with a low-level controller that produces trajectories resultingin a robust, human-like merge negotiation behavior.

The present disclosure plans high-quality merging behaviors under densetraffic conditions for an autonomous vehicle. Its presence within anautomated driving architecture guarantees greater safety, comfort, andreliability in the often-encountered dense traffic condition. The systemof the present disclosure automatically detects a need for merging andaccomplishes a human-like negotiation of merging into dense traffic,whereby a proactive shifting behavior towards the target lane isexecuted by a low-level controller to disambiguate the intentions of thevehicles in the target lane. The system also achieves robustness byintegrating robust planning under uncertainty about the intentions ofvehicle in the other lanes, to ensure the vehicle merges only when thereis sufficiently high probability of success.

FIG. 1 illustrates a vehicle 10 having an autonomous drive system 14 inaccordance with the present disclosure. The vehicle 10 may be anyvehicle suitable for being outfitted with an autonomous drive system forautonomously driving the vehicle and monitoring driving conditionswithout requiring input from an operator. The vehicle 10 may be anysuitable passenger vehicle, utility vehicle, commercial vehicle,recreational vehicle, mass transit vehicle, motorcycle, militaryvehicle/equipment, construction vehicle/equipment, etc.

With additional reference to FIG. 2, the autonomous drive system 14generally includes a perception module 18, an intention predictionmodule 22, a location module 26, and a control module 30. In thisapplication, the term “module” may be replaced with the term “circuit.”The term “module” may refer to, be part of, or include processorhardware (shared, dedicated, or group) that executes code and memoryhardware (shared, dedicated, or group) that stores code executed by theprocessor hardware. The code is configured to provide the features ofthe modules described herein. The term memory hardware is a subset ofthe term computer-readable medium. The term computer-readable medium, asused herein, does not encompass transitory electrical or electromagneticsignals propagating through a medium (such as on a carrier wave). Theterm computer-readable medium is therefore considered tangible andnon-transitory. Non-limiting examples of a non-transitorycomputer-readable medium are nonvolatile memory devices (such as a flashmemory device, an erasable programmable read-only memory device, or amask read-only memory device), volatile memory devices (such as a staticrandom access memory device or a dynamic random access memory device),magnetic storage media (such as an analog or digital magnetic tape or ahard disk drive), and optical storage media (such as a CD, a DVD, or aBlu-ray Disc).

The autonomous drive system 14 may communicate with environmentperception sensors 34, a transmitter/receiver 38, and a driver interface42 located throughout the vehicle 10, among other things. Theenvironment perception sensors 34 are any sensors configured tosense/perceive/detect features of the environment about the vehicle 10,such as roadway boundaries, lane markers, other vehicles, pedestrians,buildings, tunnels, bridges, weather conditions, road conditions, andany other obstacles about the vehicle 10. The environment perceptionsensors 34 may also sense/perceive/detect/measure features of thevehicle 10, such as velocity, acceleration, and other vehicleparameters. The environment perception sensors 34 can include anysuitable radar sensor, LIDAR sensor, sonar sensor, cameras, etc.

The transmitter/receiver 38 can be any suitable transmitter/receiver,such as for radio frequency transmission and reception. Thetransmitter/receiver 38 includes, for example, any suitable antennamounted at any appropriate location about the vehicle 10.

The driver interface 42 may include any communication system with anoperator of the vehicle. The driver interface 42 may include a driverinput on the interior of the vehicle, such as, for example, on thedashboard or the display panel. The driver interface 42 may receive,among other things, instructions from the driver for destinations and/orpreferred routes.

The perception module 18 is configured to detect and track othervehicles on the road in both a current lane 46 of the vehicle 10 andneighboring lanes 50 (FIG. 3). The perception module 18 receives signalsfrom the environment perception sensors 34 and the transmitter/receiver38 including data on surrounding vehicles (for example, vehicles10-1-10-9), such as, for example, position, velocity, acceleration,orientation, etc. The data may be measured, or estimated, data from theenvironment perception sensors 34 on the vehicle 10. The data may alsobe provided from the surrounding vehicles through vehicle-to-vehiclecommunication methods and received by the vehicle 10transmitter/receiver 38.

The intention prediction module 22 communicates with the perceptionmodule 18. The intention prediction module 22 takes as input the statesfor the vehicles on the current 46 and neighboring 50 lanes and makespredictions as to their future behaviors in the form of timeparameterized trajectories and associated likelihoods. For example, theintention prediction module 22 makes predictions as to whether thevehicles will speed up, slow down, maintain current velocities, maintainclose following distances, allow gaps, change lanes, etc., and transmitsthese predictions as trajectories over estimated periods of times. Theintention prediction module 22 outputs the predicted possibletrajectories of the surrounding vehicles to the control module 30.

The location module 26 is configured to identify the location of thevehicle 10 in any suitable manner. For example, the location module 26can include a GPS receiver configured to receive signals from GPS orGNSS satellites, and determine the location of the vehicle 10 based onthe signals. The location module 26 may also be a combined GPS and IMU(inertial measurement unit) sensor. The location of the vehicle 10 canbe transmitted by the transmitter/receiver 38 to other vehicles in thevicinity.

The control module 30 is configured to pilot the vehicle 10 withoutrequiring input of an operator of the vehicle 10. Thus, the controlmodule 30 is configured to receive initial instructions from the driverinterface 42, receive signals from the environment perception sensors34, the transmitter/receiver 38, the location module 26, and theintention prediction module 22, and to at least accelerate, decelerate,and steer the vehicle 10 to drive the vehicle 10 to a desired location.

The control module 30 receives the predicted possible trajectories ofthe surrounding vehicles from the intention prediction module 22 anddetermines a lowest risk location and time for a lane change or merge.The control module 30 will determine which pair of vehicles betweenwhich the merge should be attempted and at what time the merge shouldoccur.

Although the control module 30 is illustrated and described as a singlemodule, it is understood that the control module 30 may be a pluralityof modules configured to collectively pilot the vehicle 10 without inputof an operator. In some embodiments, the control module 30 may be splitinto a plurality of modules, such as, for example, a planning module anda controller module.

With reference to FIG. 3, the vehicle 10 is illustrated in an exampledense traffic condition. The perception module 18 is configured todetect and track vehicles 10-1-10-9 (collectively 10-X) in current laneand neighboring lanes of the vehicle 10. The perception module 18communicates the vehicle status to the intention prediction module 22which makes predictions as to the future behaviors of vehicles 10-X inthe form of time parameterized trajectories. The time parameterizedtrajectories for vehicles 10-X are communicated to the control module 30which determines a lowest risk location and time for the merge.

For example, if the vehicle 10 has the intention to merge into targetlane 54, the control module 30 may determine that a lowest risk locationto merge is between vehicles 10-8 and 10-9 (i.e., target vehicles ortarget vehicle pair) based on the trajectories of vehicles 10-6-10-9 and10-4. The control module 30 may also determine the optimum time based ona prediction that vehicle 10-8 will decelerate in, for example, 5seconds, creating a gap between vehicles 10-8 and 10-9.

Based on the control module's formulated policy or plan, the controlmodule 30 will pilot the vehicle 10 to move into position to merge intothe target lane 54 and execute the merge within the plan. Failures toachieve the goal of the plan, i.e. failures to merge, are handled byentering a failure recovery where the control module 30 pilots thevehicle 10 safely back in the original lane.

With reference to FIG. 4, an example method 100 of a lane changemaneuver, and more specifically, a lane merge under dense trafficconditions, is illustrated. While the present disclosure is described asbeing utilized under dense traffic conditions, dense traffic conditionsare not necessary for execution of method 100. Method 100 may beperformed by control module 30 upon receipt of the time parameterizedtrajectories for vehicles 10-X.

Method 100 starts at 104. At 108 the control module 30 initiates themerge process. The merge process is generally initiated by the controlmodule 30 based on the planned route selected by the operator of thevehicle. At 112, the control module 30 determines a policy or plan forthe merge. The control module 30 makes the determination based on thetime parameterized trajectories for vehicles 10-X received from theintention prediction module 22. For example, the control module 30 maydetermine the policy or plan of merging into target lane 54 betweentarget vehicles 10-8, 10-9 based on the lowest risk merge path.

At 116, the vehicle 10 enters a “waiting to shift” state. During the“waiting to shift” state, the control module 30 requires the vehicle 10to meet predetermined criteria for certain named environmentalconditions. For example only, the named environmental conditions mayinclude location of the vehicle 10, location of the target vehicle (forexample, vehicle 10-9), velocity of the vehicle 10, velocity of thetarget vehicle (for example, vehicle 10-9), etc. The predeterminedcriteria may include threshold ranges for a difference between thelocations of the vehicle 10 and the target vehicles 10-8, 10-9, adifference between the velocities of the vehicle 10 and the targetvehicles 10-8, 10-9, etc. An example “waiting to shift” state isillustrated in FIG. 5A. As illustrated, the vehicle 10 advances in itslocation relative to a lead target vehicle 10-9 and a target vehicle10-8.

At 120, the control module 30 determines whether there has been a timeout, a signal to abort the merge, or imminent risk. The time out mayoccur at a predetermined time threshold. The predetermined timethreshold may be a function of the velocity of the vehicle 10 and may beset to ensure that the system 14 does not get “stuck” in the “waiting toshift” state. For example only, the time out may be set within a rangeof 5 to 10 seconds (s) at 40 miles per hour (mph).

The signal to abort the merge may be provided by an external componentin the vehicle 10 or by the operator. For example only, the operator ofthe vehicle could discontinue autonomous vehicle control or enter adifferent or new route. Either of these options may trigger a signal toabort the merge.

Imminent risk may be determined if a surrounding vehicle's 10-Xintention or function is different than the prediction generated by theintention prediction module 22. For example, if the prediction ofsurrounding vehicle 10-X is to slow and create a gap for the merge, andthe actual actions of the vehicle 10-X are to speed up, the merge planof the vehicle 10 is no longer low risk, and an imminent risk istriggered.

If true at 120, the control module 30 initiates failure mode andrecovery at 124. In the failure mode and recovery, the control module 30terminates the merge plan or policy and directs the vehicle back to theoriginal lane 46 safely. The control module 30 then switches to ageneric planner at 128 and ends at 132.

If false at 120, the control module 30 determines whether the vehicle 10passes a shifting condition check at 136. The shifting condition checkmay include determining whether the vehicle 10 has met the predeterminedcriteria for the certain named environmental conditions previouslydiscussed. For example only, the shifting condition check may includedetermining whether a difference in the velocity of the vehicle 10 andeach of the target vehicles 10-8, 10-9 is within a predetermined range,such as 0-2 mph, and whether a difference in the locations or positionsof the vehicle 10 and each of the target vehicles 10-8, 10-9 is at leasta predetermined threshold, such as 5 feet (ft.).

If false at 136, method 100 returns to 116. If true at 136, the controlmodule 30 transitions to a shifting state at 140. During the shiftingstate the control module 30 controls the vehicle to shift towards thetarget lane 54. An example of the shifting state is illustrated in FIG.5B. As illustrated, the vehicle 10 moves in a direction toward theleader target vehicle 10-9 and slightly crosses over a lane delimiter 58(or “lane delimiter marking” or “lane marking line”) to indicate thevehicle's 10 intention to merge.

At 144, the control module 30 determines whether there has been a timeout, a signal to abort the merge, or imminent risk. The signal to abortthe merge and the imminent risk may be the same as those described inrelation to 120. The time out may occur at a predetermined timethreshold. The predetermined time threshold may be the same aspreviously described in relation to 120 or may be different based on thedifferent state. The predetermined time threshold may be a function ofthe velocity of the vehicle 10 and may be set to ensure that the system14 does not get “stuck” in the “shifting” state. For example only, thetime out may be set within a range of 2-5 s at 40 mph.

If true at 144, the control module 30 initiates failure mode andrecovery at 124. In the failure mode and recovery, the control module 30terminates the merge plan or policy and directs the vehicle back to theoriginal lane 46 safely. The control module 30 then switches to ageneric planner at 128 and ends at 132.

If false at 144, the control module 30 determines whether shifting iscompete at 148. Shifting may be complete, for example, once the vehicle10 crosses over the lane delimiter 58.

If false at 148, method 100 returns to 140. If true at 148, the controlmodule 30 transitions to a “waiting to merge” state at 152. During the“waiting to merge” state, the control module 30 requires the vehicle 10to meet predetermined criteria for certain named environmentalconditions. For example only, the named environmental conditions mayinclude location of the vehicle 10, location of the target vehicle (forexample, vehicle 10-9), velocity of the vehicle 10, velocity of thetarget vehicle (for example, vehicle 10-9), etc. The predeterminedcriteria may include threshold ranges for a difference between thelocations of the vehicle 10 and the target vehicles 10-8, 10-9, adifference between the velocities of the vehicle 10 and the targetvehicles 10-8, 10-9, etc. An example “waiting to merge” state isillustrated in FIG. 5C. As illustrated, the vehicle 10 maintains itsshifted location over the lane delimiter 58 and waits for lead targetvehicle 10-9 and target vehicle 10-8 to create a gap for merging.

At 156, the control module 30 determines whether there has been a timeout, a signal to abort the merge, or imminent risk. The signal to abortthe merge and the imminent risk may be the same as those described inrelation to 120. The time out may occur at a predetermined timethreshold. The predetermined time threshold may be the same aspreviously described in relation to 120 or 144, or may be differentbased on the different state. The predetermined time threshold may be afunction of the velocity of the vehicle 10 and may be set to ensure thatthe system 14 does not get “stuck” in the “waiting to merge” state. Forexample only, the time out may be set within a range of 5-10 s at 40mph.

If true at 156, the control module 30 initiates failure mode andrecovery at 124. In the failure mode and recovery, the control module 30terminates the merge plan or policy and directs the vehicle back to theoriginal lane 46 safely. The control module 30 then switches to ageneric planner at 128 and ends at 132. The generic planner is a portionof the control module 30 that generates instructions for generaloperation of the vehicle. For example only, the generic plannergenerates instructions for accelerating, decelerating, following trafficsignals, executing turns, etc. under normal driving conditions.

If false at 156, the control module 30 determines whether the vehicle 10passes a merging condition check at 160. The merging condition check mayinclude determining whether the vehicle 10 has met the predeterminedcriteria for the certain named environmental conditions previouslydiscussed. For example only, the merging condition check may includedetermining whether a difference in the velocity of the vehicle 10 andeach of the target vehicles 10-8, 10-9 is within a predetermined range,such as 0-2 mph, and whether a difference in the locations or positionsof the target vehicles 10-8, 10-9 is at least a predetermined threshold,such as 15 ft.

If false at 160, method 100 returns to 152. If true at 160, the controlmodule 30 transitions to a merging state at 164. In the merging state,the control module 30 directs the vehicle 10 to merge into the targetlane 54. An example of the merge state is illustrated in FIG. 5D. Asillustrated, the vehicle 10 merges between the lead target vehicle 10-9and the target vehicle 10-8 in the target lane 54, completing the merge.

At 168, the control module 30 determines whether there has been a timeout, a signal to abort the merge, or imminent risk. The signal to abortthe merge and the imminent risk may be the same as those described inrelation to 120. The time out may occur at a predetermined timethreshold. The predetermined time threshold may be the same aspreviously described in relation to 120, 144 or 156, or may be differentbased on the different state. The predetermined time threshold may be afunction of the velocity of the vehicle 10 and may be set to ensure thatthe system 14 does not get “stuck” in the merging state. For exampleonly, the time out may be set within a range of 2-5 s at 40 mph.

If true at 168, the control module 30 initiates failure mode andrecovery at 124. In the failure mode and recovery, the control module 30terminates the merge plan or policy and directs the vehicle back to theoriginal lane 46 safely. The control module 30 then switches to ageneric planner at 128 and ends at 132.

If false at 168, the control module 30 determines whether the merge iscomplete at 172. The merge may be complete if, for example, all wheelshave crossed over the lane delimiter 58. If false, method 100 returns to164. If true at 172, the control module 30 returns a merge success stateat 176. The method 100 then ends at 132.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. An autonomous drive system for a vehiclecomprising: at least one environment perception sensor located on thevehicle, the at least one environment perception sensor being configuredto detect at least one of a position, velocity, acceleration, andorientation of a vehicle within a detection range of the at least oneenvironment perception sensor; a perception circuit configured toreceive signals from the at least one environment perception sensor anddetect and track a first remote vehicle and a second remote vehicle inone or both of a current lane and a neighboring lane; a location circuitconfigured to determine a location of the vehicle; an intentionprediction circuit configured to generate predicted trajectories for thefirst remote vehicle and the second remote vehicle, the intentionprediction circuit being configured to generate the predictedtrajectories from velocities, accelerations, orientations, and positionsof the first remote vehicle and the second remote vehicle tracked by theperception circuit, the predicted trajectories generated by theintention prediction circuit providing predictions for whether the firstremote vehicle and the second remote vehicle will speed up, slow down,maintain current velocities, maintain close following distances, allowgaps, and change lanes; and a controller configured to receive signalsfrom the at least one environment perception sensor and receive thepredicted trajectories from the intention prediction circuit, whereinthe controller determines a location and time for a lane change based onthe predicted trajectories and controls the vehicle to change lanes atthe determined location and time.
 2. The autonomous drive system ofclaim 1, wherein the controller completes a waiting to shift stage, ashifting stage, a waiting to merge stage, and a merging stage when thecontroller controls the vehicle to change lanes at the determinedlocation and time.
 3. The autonomous drive system of claim 2, whereinthe controller determines whether a distance between the vehicle andeach of the first remote vehicle and the second remote vehicle is lessthan a predetermined distance threshold and whether a difference in avelocity of the vehicle and velocities of the first remote vehicle andthe second remote vehicle is less than a predetermined velocitythreshold during the waiting to shift stage.
 4. The autonomous drivesystem of claim 2, wherein the controller shifts the vehicle in adirection toward a lead vehicle of the first remote vehicle and thesecond remote vehicle during the shifting stage.
 5. The autonomous drivesystem of claim 4, wherein the shifting stage is complete when thecontroller controls the vehicle to cross over a lane delimiter and intothe neighboring lane.
 6. The autonomous drive system of claim 2, whereinthe controller determines whether a distance between the first remotevehicle and the second remote vehicle is greater than a predetermineddistance threshold and whether a difference in a velocity of the vehicleand velocities of the first remote vehicle and the second remote vehicleis less than a predetermined velocity threshold during the waiting tomerge stage.
 7. The autonomous drive system of claim 2, wherein thecontroller shifts the vehicle into the neighboring lane from the currentlane at the determined location and time during the merging stage. 8.The autonomous drive system of claim 7, wherein the merging stage iscomplete when the vehicle has completely crossed over a lane delimiterand the neighboring lane becomes a new current lane for the vehicle. 9.The autonomous drive system of claim 2, wherein if a time spent in astage exceeds a predetermined threshold, the controller initiates amerge failure recovery and controls the vehicle back into the currentlane.
 10. The autonomous drive system of claim 2, wherein, if an abortsignal is received or if one of the first remote vehicle and the secondremote vehicle follows a path different than the predicted trajectoriesthat increases a risk as determined by the intention prediction circuit,the controller initiates a merge failure recovery and controls thevehicle back into the current lane.
 11. A method for controlling anautonomous vehicle comprising: determining, by a location circuit, alocation of the autonomous vehicle; detecting, by at least oneenvironment perception sensor located on the autonomous vehicle, atleast one of a position, velocity, acceleration, and orientation, of atleast one remote vehicle within a detection range of the at least oneenvironment perception sensor; detecting and tracking, by a perceptioncircuit, an output of the at least one environment perception sensor fora first remote vehicle and a second remote vehicle in one or both of acurrent lane and a neighboring lane; generating, by an intentionprediction circuit, predicted trajectories for the first remote vehicleand the second remote vehicle from velocities, accelerations,orientations, and position of the first remote vehicle and the secondremote vehicle tracked by the perception circuit, the predictedtrajectories generated by the intention prediction circuit providingpredictions for whether the first remote vehicle and the second remotevehicle will speed up, slow down, maintain current velocities, maintainclose following distances, allow gaps, and change lanes; determining, bya controller, a location and time for a lane change based on thepredicted trajectories for the at least two remote vehicles; andcontrolling, by the controller, the vehicle to change lanes at thedetermined location and time.
 12. The method of claim 11, furthercomprising completing, by the controller, a waiting to shift stage, ashifting stage, a waiting to merge stage, and a merging stage whilecontrolling, by the controller, the vehicle to change lanes at thedetermined location and time.
 13. The method of claim 12, furthercomprising determining, by the controller, whether a distance betweenthe vehicle and each of the first remote vehicle and the second remotevehicle is less than a predetermined distance threshold and whether adifference in a velocity of the vehicle and velocities of the firstremote vehicle and the second remote vehicle is less than apredetermined velocity threshold during the waiting to shift stage. 14.The method of claim 12, further comprising shifting, by the controller,the vehicle in a direction toward a lead vehicle of the first remotevehicle and the second remote vehicle during the shifting stage.
 15. Themethod of claim 14, further comprising completing, by the controller,the shifting stage when the vehicle crosses over a lane delimiter andinto the neighboring lane.
 16. The method of claim 12, furthercomprising determining, by the controller, whether a distance betweenthe first remote vehicle and the second remote vehicle is greater than apredetermined distance threshold and whether a difference in a velocityof the vehicle and velocities of the first remote vehicle and the secondremote vehicle is less than a predetermined velocity threshold duringthe waiting to merge stage.
 17. The method of claim 12, furthercomprising controlling, by the controller, the vehicle to change lanesbetween the current lane and the neighboring lane at the determinedlocation and time during the merging stage.
 18. The method of claim 17,further comprising completing, by the controller, the merging stage whenthe vehicle has completely crossed over a lane delimiter and theneighboring lane becomes a new current lane for the vehicle.
 19. Themethod of claim 12, further comprising initiating, by the controller, amerge failure recovery if a time spent in a stage exceeds apredetermined time threshold, and controlling, by the controller, thevehicle back into the current lane.
 20. The method of claim 12, furthercomprising initiating, by the controller, a merge failure recovery if anabort signal is received or if one of the first remote vehicle and thesecond remote vehicle follows a path different than the predictedtrajectories that increases a risk as determined by the intentionprediction circuit, and controlling, by the controller, the vehicle backinto the current lane.